The gas turbine engine is the preferred class of internal combustion engine for many high power applications. Fundamentally, the gas turbine engine features an upstream rotating compressor coupled to a downstream turbine, and a combustion chamber in-between. One of the driving factors in modern gas turbine engine design is emissions reduction, and the combustor is the primary contributor in this regard. Combustion of the hydrocarbon fuel in air inevitably produces harmful emissions, such as oxides of nitrogen (NOx). NOx emissions are the subject of increasingly stringent controls by regulatory authorities. NOx emissions scale with the temperature of the combustion flame. The combustion flame temperature is product of several factors, including the fuel-air ratio. A lean fuel-air ratio is likely to produce less NOx emissions, but can cause problems in maintaining the stability of the combustion flame. Thus, new concepts are continuously sought to achieve low NOx emissions with a stable combustion flame.
Like reference numbers and designations in the various drawings indicate like elements.